1. Field of the Invention
This invention relates to the oil and gas industry and more particularly to environmentally acceptable recycling drilling mud, brine and the by products thereof.
Oil and gas wells may be drilled in environmentally sensitive areas. One such area is that of bedrock aquifers and their recharge zones. Aquifers are strata or zones below the surface of the earth capable of producing water with human consumptive potential. The consumptive potential may be in the form of drinking water, or in the form of irrigation for agricultural crops.
Oil and gas well drilling mud, a suspension of generally aqueous fluid and emulsions, is used to seal off porous zones, and to counter-balance pressures encountered. Salt water including oil may be used as a vehicle instead of fresh water. The drilling mud usually consists of various substances in a finely divided state such as bentonite and barite.
Drilling mud carries the drill formation cuttings to the surface for disposal. Approximately two feet of oil well drilled footage requires one barrel of mud fluids. The drilling mud additives vary from region to region and from well to well. Since large and varying volumes of drilling fluids are needed to drill an oil well it is environmentally as well economically desirable to reuse, recycle or ultimately destroy these otherwise deleterious substances.
Oil and gas fields produce more and more salt water, herein called "brine". The brine consists of relative percentages of other economic units such as iodine, sodium bromide, sodium chloride, sodium iodide, calcium chloride, magnesium, potash, iron, potassium chloride, and aluminum. When brine is electrolyzed hydrogen gas (H.sub.2) and chlorine gas (CL.sub.2) are produced at the electrodes which can be reused and recycled. Brine may act as a contaminant to fresh water aquifers if not properly disposed of.
2. Description of the Prior Art
The most pertinent patent is believed to be U.S. Pat. No. 4,696,353 which discloses a mud cleaning system for recovering barite from drilling mud coming from an oil well, the mud being made up essentially of barite particles having a specific gravity of 4.2 or more, and a particle size mostly finer than 200 mesh, drill cuttings having a specific gravity of 2-3, and varying particle sizes ranging from about 200 mesh to one-half inch or more, and water. This system includes a first sieve bend, a second screen member in series therewith, and a spiral separator, in series with the screens. The sieve bend is provided with a vibrator and water sprays act in conjunction with the sieve bend and the second screen to aid in separation. The slurry leaving the spiral separator is screened to remove the ultra fines particles and the water is recycled. The system inherently washes potentially environmentally hazardous substances off the drill cuttings prior to their discharge from the system.
This invention is distinctive over this and other prior art patents by reducing drilling mud and brine to their respective elements which are useful in respective industries.